[KevinH]

Are these .dic_delta files pure text lists of words one per line like our UserDictionaries or do they have a specific format?

What if the existing UserDictionary file name does not include the language and region? For example, how would your naming convention work with the "default" user dictionary Sigil sets normally?

I guess we could assume that the default dictionary to always be the same language and locale as the Primary Dictionary setting, whatever the user sets for that.

The same question holds for all people's existing UserDictionaries. I guess we could again assume all existing UserDictionaries are in the Primary Dictionary language and region and copy and rename them in the next release to the form (replacing the en_US with whatever the primary dictionary is):

en_US_previousname.dic_delta

Then all future releases could use that approach. Or maybe better yet, we could provide an official Sigil plugin to convert all existing UserDictionaries to the new naming format?

I wonder how many users of Sigil make extensive use of its UserDictionaries feature? I do not.

If we decide to use language specific ignore lists, we can follow along in the same fashion.

All feedback welcome.